Risk of Developing Comorbidities Among Women with Endometriosis: A Retrospective Matched Cohort Study

Background: Endometriosis has been associated with higher rates of various chronic conditions, but its epidemiological data are fragmented and dated. We sought to compare the incidence of developing commonly occurring comorbidities among patients with and without endometriosis in a large, contemporary patient cohort that reflects real-world clinical practice. Materials and Methods: A cohort of women aged 18–49 with incident endometriosis was extracted from the 2006–2015 de-identified Clinformatics® DataMart commercial insurance claims database (OptumInsight, Eden Prairie, MN). Endometriosis was identified by International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code 617.x on ≥1 inpatient or emergency department claim or ≥2 outpatient claims. Nonendometriosis control patients were exactly matched 4:1 to cases based on state, insurance plan type, and age (±1 year). Based on a literature review and expert consultation, 22 comorbidities were identified for analysis. The risk of developing a comorbidity post-index date was analyzed with stratified Cox proportional hazards models. Results: There were 26,961 cases and 107,844 controls. Mean age was 36 years. The adjusted risk of developing a comorbid condition among endometriosis cases was statistically significantly higher than the matched controls for all 22 comorbidities (p ≤ 0.001) and was at least twice as large for nine comorbidities (infertility/subfertility, ovarian cyst, uterine fibroids, pelvic inflammatory disorder, interstitial cystitis, irritable bowel syndrome, constipation/dyschezia, ovarian cancer, and endometrial cancer). Conclusion: The incidence of developing many comorbidities was significantly higher among endometriosis patients compared with matched women without endometriosis. Additional research is needed to establish the implications for healthcare resource use.